The present invention relates to a fuel control system, and more particularly to an oxygen sensor used with a catalytic converter in a system for feedback control of an air/fuel ratio in the mixture supplied to an internal combustion engine of a vehicle.
There have been proposed air/fuel ratio feedback control systems detecting deterioration of catalytic converters by using oxygen sensors.
Japanese Patent Application First Publication No. 2-136538 discloses an air/fuel ratio feedback control system which includes an oxygen sensor disposed on a downstream side of a catalytic converter.
Japanese Patent Application First Publication No. 4-17758 discloses an air/fuel ratio feedback control system which includes oxygen sensors disposed on both upstream and downstream sides of a catalytic converter.
One example of prior art catalytic converters includes a tubular shell disposed beneath a floor of a vehicle. The tubular shell defines an exhaust path and receives a catalyst module. One example of conventional oxygen sensors includes a space communicating with the exhaust path and a sensing element within the space.
Japanese Utility Model Application First Publication No. 59-17854 discloses one example of such oxygen sensors.